Run execution plan analysis on SELECT and WITH queries to generate structured reports that identify PostgreSQL performance bottlenecks and guide query optimization.
Run EXPLAIN ANALYZE on a SELECT query and return a structured report.
Args: sql: A SQL query. Only SELECT and WITH statements are allowed.
| Name | Required | Description | Default |
|---|---|---|---|
| sql | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries full responsibility for behavioral disclosure. It usefully notes that only SELECT and WITH statements are allowed, but it does not mention that EXPLAIN ANALYZE actually executes the query and may be resource-intensive, nor does it address error behavior. This is adequate but leaves notable behavioral traits implicit.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is compact and well-structured: a single front-loaded sentence states the action and output, followed by a minimal Args block. Every line earns its place with no filler or repetition.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The description covers the core call requirements: the operation, the output, and the parameter constraint. The output schema supplies return structure. However, for a tool with no annotations, it should also mention that EXPLAIN ANALYZE executes the query, which affects cost and safety expectations, and provide clearer usage context.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 0%, but the description compensates by defining sql as 'A SQL query' and adding the important SELECT/WITH restriction. For a single self-explanatory parameter, this is sufficient, though it omits minor details like whether semicolons or parameterized queries are accepted.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description opens with a specific verb-resource pair ('Run EXPLAIN ANALYZE on a SELECT query') and states the deliverable ('structured report'). This makes the tool's purpose immediately clear and distinguishes it from sibling tools ping and list_tables without ambiguity.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Usage context is implied: an agent would use this when it needs an EXPLAIN ANALYZE report for a SELECT/WITH query. However, the description does not explicitly state when to prefer this tool over alternatives or provide any exclusionary guidance beyond the allowed statement types.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.